This proposal requests funds to purchase a Zeiss LSM 510 META laser confocal microscope system and image processing accessories to be used by investigators from of the Departments of Medical and Molecular Parasitology and Pathology at the New York University School of Medicine. Since the shared Confocal Microscopy Facility of the Skirball Institute was discontinued and access to the Zeiss LSM 510 in the Department of Cell Biology was restricted, parasitology faculty can no longer perform confocal microscopy at NYUSM. A shared confocal microscopy facility is therefore essential to continue ongoing research and to start new projects. This facility is expected to strongly enhance new projects, foster the opening of new areas of investigation, and intensify current collaborations among participating investigators. Because the confocal facility will be located in close proximity to insectaries and cell culture and animal facilities, it will enable many of the investigators to perform, for the first time, dynamic studies using living parasites. Confocal Microscopy will be an essential tool for the major research projects included in this proposal, allowing the participants to investigate relationships between various protozoan parasites and their host cells as well as mechanisms of interaction between infected cells and the immune system of the host. Most of the proposed projects involve the examination of parasites as well as various mammalian cell types and tissues at a subcellular level, with a strong emphasis on live cell studies. The experimental approaches being used in these various projects are quite diverse, involving molecular and cell biological methodologies, as well as immunological and biochemical techniques. Due to the small size of many of the intracellular microorganisms and cell organelles under investigation, and the emphasis on subcellular localization and intracellular transport, the planned studies require the most advanced instrumentation available. This instrumentation must be capable of providing the highest obtainable resolution and a high efficiency of light detection, as well as the most precise registration of multiple channels scanned simultaneously or sequentially that is currently available. For effective use as a shared resource for parasitology studies, the system must be user friendly, must operate efficiently in terms of the time required to obtain the data, and must be located in the Department of Medical and Molecular Parasitology. All these requirements can be met by a shared Zeiss LSM 510 META laser scanning confocal system.